Filter for cleaning a fluid

ABSTRACT

A filter for filtering a fluid has a filter housing and a filter element arranged in the filter housing. A cyclone preseparator is arranged upstream of the filter element, wherein a fluid to be cleaned is guided through the preseparator to the filter element. The cyclone preseparator has at least two cyclone cells that have a different diameter, respectively.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of internationalapplication PCT/EP2007/062978 having a filing date of 29 Nov. 2007, thecontents of which are incorporated herein by reference in its entirety,and claims the benefit under 35 USC 119 of the filing date of foreignapplication DE 20 2007 004 476.3 filed in Germany on 23 Mar. 2007, thecontents of which are incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

The present invention relates to a filter for cleaning a fluid, inparticular a gaseous fluid, comprising a filter element arranged in afilter housing and a cyclone preseparator that is arranged upstream ofthe filter element and by means of which the fluid can be guided intothe filter element.

DE 20 2005 009 989 U1 discloses an air filter that is integrated intothe intake manifold of an internal combustion engine in order to subjectthe combustion air to be supplied to the internal combustion engine to afiltration process. The air filter is of a multi-part configuration andcomprises a filter element arranged in a filter housing and having acyclone preseparator as a prefilter arranged upstream thereof. A finefilter is arranged downstream. The cyclone preseparator that has thetask to separate the coarse dirt particles contained in the unfilteredair comprises a plurality of parallel arranged tubular flow passages ofsame diameter. These flow passages open into an ante chamber arranged infront of the filter element in the filter housing. An outlet openingextending outwardly in the radial direction is provided at the antechamber and by means of the outlet opening the dirt particles that havebeen separated from the fluid can be removed from the preseparatorhousing.

The flow passages of identical geometry within the cyclone preseparatorare matched to a predetermined nominal throughput. Different throughputparameters require therefore a corresponding adaptation of the cyclonepreseparator. A reduction of the diameter of the flow passages in thecyclone preseparator improves the cleaning effect but reduces at thesame time the nominal throughput.

SUMMARY OF THE INVENTION

It is an object of the present invention to increase the efficiency of afilter provided with a cyclone preseparator with simple constructivemeasures.

This object is solved in that the cyclone preseparator has at least twocyclone cells that have a different diameter, respectively.

In the filter according to the invention for cleaning a fluid the filterelement arranged in the filter housing has arranged upstream thereof acyclone preseparator through which the fluid is passed before the fluidthat is pre-cleaned in this way subsequently flows through the filterelement. The cyclone preseparator comprises at least two cyclone cellsof different diameter. A cyclone cell is to be understood as anindividual cyclone provided with an inlet opening and an outlet openingand a flow passage connecting the inlet opening and the outlet opening.In the filter according to the invention at least two such cyclone cellsare integrated that have different diameters. In this way, the availablespace can be utilized better in comparison to cyclone cells of samediameter. Moreover, the average degree of separation is increased whenusing smaller cyclones in comparison to cyclones of greater andidentical diameter because the fluid flow that is supplied to the filterelement can be purified better, due in part to the higher centrifugalforces on contaminants in the fluid flow when the same flow rate ispassed through a smaller capacity/size cyclone. At the same time, theclogging tendency as a result of use of cyclone cells of greaterdiameter in comparison to the use of uniform cyclones cells of smallerdiameter is reduced. Because of the improved utilization of the spaceand adaptation of the end face of the cyclone a more uniform intake atthe downstream filter element is achieved. The uniform intake leads to alonger service life of the filter element.

The combination of several individual cyclones or cyclone cells in thefilter can be realized in various ways. One possibility is theintegration of the different cyclone cells into the filter housing ofthe filter element wherein in this embodiment the cyclone cells arefitted into the intake wall of the filter housing. However, it is alsopossible to combine various cyclone cells in a cyclone block that isarranged upstream of the filter housing and is connected to it. It isalso possible to combine both embodiments so that different cyclonecells are combined into a cyclone block that is integrated into thefilter housing.

According to an expedient embodiment the free flow cross-section of thegreater cyclone cell differs by at least the factor 2 from the free flowcross-section of the smaller cyclone cell. In this way, a minimum sizedifference is predetermined which, on the one hand, has advantages withregard to space utilization because the small cyclone cells can beinserted into niches between greater cyclone cells or one greatercyclone cell and the sidewall. On the other hand, advantages areachieved with respect to the degree of separation or the utilizationspectrum because by means of the greater cyclones the air throughput andby means of the smaller cyclones the degree of separation are increased.Advantageously, a size difference between large and small cyclone cellsis desirable that is, for example, greater by the factor 3 or evengreater than the factor 3.

A plurality of cyclone cells of same diameter can be provided, forexample, two cyclone cells of the same greater diameter, respectively,and two cyclone cells of the same smaller diameter, respectively, can beprovided that are distributed across the intake side of the filter. Foran appropriate size difference the cyclone cells for an oval filterhousing can be expediently distributed in such a way that the twogreater cyclone cells are positioned sequentially behind one another inthe direction of the major axis of the oval shape and the two smallercyclone cells are positioned in a transverse direction thereto.

The above features and advantages and other features and advantages ofthe present invention are readily apparent from the following detaileddescription of the best modes for carrying out the invention when takenin connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying Figures, where like reference numerals refer toidentical or functionally similar elements throughout the separate viewsand which together with the detailed description below are incorporatedin and form part of the specification, serve to further illustratevarious embodiments and to explain various principles and advantages allin accordance with the present invention.

Features of the present invention, which are believed to be novel, areset forth in the drawings and more particularly in the appended claims.The invention, together with the further objects and advantages thereof,may be best understood with reference to the following description,taken in conjunction with the accompanying drawings. The drawings show aform of the invention that is presently preferred; however, theinvention is not limited to the precise arrangement shown in thedrawings.

FIG. 1 shows a perspective illustration of a filter that is flownthrough axially by a fluid to be cleaned wherein the filter housing ofthe filter has integrated therein a cyclone preseparator at the intakeside which cyclone preseparator is comprised of two larger and twosmaller individual cyclones or cyclone cells;

FIG. 2 shows the filter of FIG. 1 in a perspective view onto the outletside;

FIG. 3 shows an end face view of the intake side of the filter;

FIG. 4 is a sectional illustration of the filter according to sectionline IV-Iv of FIG. 3; and

FIG. 5 is a sectional illustration according to section line V-V of FIG.3.

Skilled artisans will appreciate that elements in the figures areillustrated for simplicity and clarity and have not necessarily beendrawn to scale. For example, the dimensions of some of the elements inthe figures may be exaggerated relative to other elements to help toimprove understanding of embodiments of the present invention.

DETAILED DESCRIPTION

Before describing in detail embodiments that are in accordance with thepresent invention, it should be observed that the embodiments resideprimarily in combinations of method steps and apparatus componentsrelated to a filter for cleaning a fluid, in particular a gaseous fluidpossibly having particulate contaminants as disclosed herein.Accordingly, the apparatus components have been represented whereappropriate by conventional symbols in the drawings, showing only thosespecific details that are pertinent to understanding the embodiments ofthe present invention so as not to obscure the disclosure with detailsthat will be readily apparent to those of ordinary skill in the arthaving the benefit of the description herein.

In this document, relational terms such as first and second, top andbottom, and the like may be used solely to distinguish one entity oraction from another entity or action without necessarily requiring orimplying any actual such relationship or order between such entities oractions. The terms “comprises,” “comprising,” or any other variationthereof, are intended to cover a non-exclusive inclusion, such that aprocess, method, article, or apparatus that comprises a list of elementsdoes not include only those elements but may include other elements notexpressly listed or inherent to such process, method, article, orapparatus. An element preceded by “comprises . . . a” does not, withoutmore constraints, preclude the existence of additional identicalelements in the process, method, article, or apparatus that comprisesthe element.

The filter 1 illustrated in FIG. 1 is in particular a gas filter,preferably an air filter that is arranged in the intake manifold of aninternal combustion engine. The filter 1 comprises a two-part filterhousing 2 whose housing parts 2 a and 2 b are connected to one anotherby a releasable closure device 3. In the area of the intake side 4 acyclone preseparator 5 is integrated into the filter housing 4 and iscomprised of several cyclone cells 6 and 7 through which the fluid to besupplied is passed upon intake into the filter housing 2. The individualcyclones or cyclones cells 6, 7 each are provided with vanes throughwhich the axially incoming fluid is imparted with an angular momentum sothat dirt particles contained in the fluid as a result of centrifugalforce are transported outwardly in the interior of the filter housing 2.By means of a discharge opening 8 located in the front end section ofthe filter housing 2 that is correlated with the cyclone preseparator 5,the separated dirt particles can be removed from the housing.

In the interior of the filter housing 2, downstream of the cyclonepreseparator 5, the filter element is arranged through which the fluid,pre-cleaned in the preseparator, passes axially. By means of outletopening 9 (FIG. 2) at the end face of the filter housing 2 that isopposite the cyclone preseparator the purified fluid is discharged fromthe filter 1.

As can be seen in FIGS. 4 and 5 in connection with FIG. 3, each cyclonecell 6, 7 is comprised of an inlet section 6 a and 7 a, respectively, aflow passage 6 b and 7 b, respectively, and an outlet section 6 c and 7c. In the flow passage 6 b or 7 b the heavy dirt particles can beseparated and subsequently discharged by means of discharge opening 8 inthe filter housing. The pre-filtered fluid is then axially supplied byoutlet sections 6 c and 7 c that widen in the form of a diffuser to thefilter element 10 that is located in the central part of the filter 1.

A secondary element 11 is downstream of the filter element 10 and ispassed by the fluid coming from the filter element 10. The secondaryelement 11 has the task to protect the internal combustion engine uponexchange or damage of the filter element 10. Subsequently, the fluid isguided through the outlet opening 9 out of the filter 1.

In the foregoing specification, specific embodiments of the presentinvention have been described. However, one of ordinary skill in the artappreciates that various modifications and changes can be made withoutdeparting from the scope of the present invention as set forth in theclaims below. Accordingly, the specification and figures are to beregarded in an illustrative rather than a restrictive sense, and allsuch modifications are intended to be included within the scope of thepresent invention. The benefits, advantages, solutions to problems, andany element(s) that may cause any benefit, advantage, or solution tooccur or become more pronounced are not to be construed as a critical,required, or essential features or elements of any or all the claims.The invention is defined solely by the appended claims including anyamendments made during the pendency of this application and allequivalents of those claims as issued.

1. A filter for filtering a fluid, the filter comprising: a filterhousing; a filter element arranged in said filter housing; a cyclonepreseparator arranged upstream of said filter element in a flowdirection of a fluid to be cleaned, wherein the fluid to be cleaned isguided through said preseparator to said filter element; wherein saidcyclone preseparator comprises at least two cyclone cells that have adifferent diameter, respectively.
 2. The filter according to claim 1,wherein said at least two cyclone cells are integrated into said filterhousing.
 3. The filter according to claim 1, wherein a free flowcross-section of a first one of said at least two cyclone cells is atleast twice as large as a free flow cross-section of a second one ofsaid at least two cyclone cells.
 4. The filter according to claim 1,wherein said at least two cyclone cells are combined into a cycloneblock arranged upstream of said filter housing.
 5. The filter accordingto claim 1, wherein said at least two cyclone cells each have at leastone flow passage through which the fluid to be cleaned is guided to saidfilter element, wherein said flow passages of different ones of said atleast two cyclone cells have different diameters.
 6. The filteraccording to claim 1, wherein at least two of said cyclone cells havesame diameter.
 7. The filter according to claim 1, wherein four of saidcyclone cells are provided and wherein two of said four cyclone cellshave a first diameter and two of said cyclone cells have a seconddiameter, wherein said first diameter is larger than said seconddiameter.
 8. The filter according to claim 1, wherein said filterhousing has an oval cross-section.
 9. The filter according to claim 1,wherein said filter element is flown through in an axial direction andwherein said cyclone cells are arranged upstream of said filter elementin said axial direction.